Selectable extension stop for a polycentric hinge

Abstract

An extension stop removably mountable on a polycentric hinge for limiting the forward pivotal rotation of a pair of rigid arms pivotally connected by the hinge. The hinge is of the type wherein a pair of rigid arms are connected at spaced-apart pivotal connections between a pair of parallel face plates. Intermeshing gear teeth are provided on the mating ends of the arms so as to cause simultaneous pivotal action of both arms about their pivotal connections with the plates. The extension stop is a C-shaped plastic body which is attachable along one of the face plates. The stop includes a resilient clip for attaching the stop to one of the face plates and an extension block at the opposing end positionable between the mating ends of the arms to limit the forward rotation of the arms. The extension stop is made of a strong, lightweight plastic. Different size block means are provided to allow the user to select the limit of extension.

We claim: 
     
       1. A removable extension stop for limiting forward pivotal movement of a pair of arms connected by a polycentric hinge, said polycentric hinge being of the type including a pair of parallel spaced-apart face plates wherein the arms are pivotally secured at mating ends between the face plates at spaced-apart pivotal connections, said hinge having opposing front and rear edges, said mating ends of the arms having intermeshing gear teeth so as to cause simultaneous pivotal movement of the arms about their pivotal connections with the plates, and said mating ends of the arms having a pair of flanges adjacent the front edge of the hinge to limit the forward pivotal movement of the arms when the flanges engage the extension stop, said extension stop comprising a C-shaped body having: a clip means at one end of the body positionable adjacent the rear edge of the hinge for releasably securing the body to the hinge,   an extension block at the opposing end of the body positionable adjacent the front edge of the hinge,   and a connecting member extending between the clip means and extension block,   said extension block being positionable between the mating ends of the arms to engage the flanges and limit the forward pivotal movement of the arms toward the front edge of the hinge, and wherein said extension block has a front edge positionable adjacent the front of the hinge and a pair of diverging top and bottom edges extending from the front edge and angled outwardly toward the rear of the hinge such that the flanges cause a rearward pressure on the top and bottom edges of the block to secure the block in position on the hinge.   
     
     
       2. The extension stop of claim 1, wherein said clip means engages the rear edge of one of the face plates. 
     
     
       3. The extension stop of claim 1, wherein said body further includes a shoulder adjacent to the extension block which is shaped to fit within a complimentary shaped notch in one of the face plates. 
     
     
       4. The extension stop of claim 1, wherein said front edge of said extension block is of a predetermined size to provide an extension limit from about 0° to 40°. 
     
     
       5. The extension stop of claim 1, wherein the stop is made of plastic. 
     
     
       6. The extension stop of claim 5, where the connecting member is resilient to permit ready attachment and removal of the stop to the hinge. 
     
     
       7. The extension stop of claim 1 in combination with a knee brace wherein the stop limits the forward pivotal movement of the brace. 
     
     
       8. The combination of claim 1, wherein the pivotal connection between the mating ends of the arms and the face plates are offset forwardly of the center line of the arms. 
     
     
       9. A removable extension stop for limiting the forward pivotal movement of a pair of arms connected by a polycentric hinge, said polycentric hinge being of the type including a pair of parallel spaced-apart face plates wherein the arms are pivotally secured at mating ends between the face plates at spaced-apart pivotal connections, said hinge having opposing front and rear edges, said mating ends of the arms having intermeshing gear teeth so as to cause simultaneous pivotal movement of the arms about their pivotal connections with the plates, said rotating ends of the arms having flanges to limit the forward pivotal movement of the arms when the flanges engage the extension stop, said extension stop comprising: means for removably attaching the extension stop to the polycentric hinge; and   extension block means positionable between the mating ends of the arms to engage the flanges and to limit the forward pivotal movement of the arms, wherein said block means is disposed adjacent the front edge of the hinge and includes a pair of top and bottom edges which diverge outwardly going from the front toward the rear of the hinge so that the flanges exert a rearward pressure on the block means.